Lately, it has become possible for a controller for controlling elevators to arithmetically process a lot of information and carry out high degree control by the employment of a microcomputer.
Incidentally, several proposals are made to recent elevator control apparatuses to abolish a group management device for managing a plurality of elevators and disperse the function of the device to respective elevator control apparatuses.
For example, Japanese Unexamined Patent Publication No. 61-188376 discloses a control system arranged such that respective controllers are provided with a function for processing a call input and a call, the most significant controller of them is designated as a main station and the other controllers are designated as other stations according to a predetermined priority, the main station collects information and supplies it to the respective stations and one of the respective stations having an optimum response evaluation assigns a response to it.
Japanese Examined Patent Publication No. 5-39873 discloses a control system arranged such that each of main control units disposed in respective cars for controlling the operation thereof calculates the evaluation value of its own elevator for each landing call. Each unit inputs and outputs information such as the evaluation value and the like and responds to the landing call when its own elevator is optimally evaluated. The respective control units are connected to one another, and when a group management fails, at least one of the main control units registers a call and transmits information of a landing call to the respective control units.
Japanese Unexamined Patent Publication No. 6-80322 discloses a control system arranged such that any one of a plurality of control units is designated as a main station and the other control units are designated as substations, the main station processes a control function to be processed in real time by synchronously controlling the control units of all the elevators and the control units of the respective elevators share a control function to be cyclically processed.
Japanese Examined Patent Publication No. 6-39312 discloses a control system arranged such that a command is output from a main station to a transmission line in the state that group management is not carried out by respective control units and management is controlled by designating a control unit which controls a transmission control line at the earliest timing as a main station and the other control units are designated as subunits which follow the main unit.
However, the aforesaid prior art has the following problems. That is, although the prior arts provide the respective car controllers with a part of a group management function, they do not particularly disclose any procedure for assigning a call made at a landing and employ an assigning system based on an evaluated value like an ordinary group-managed elevator. Therefore, the respective controllers must calculate an evaluation value based on an enormous amount of information similar to an evaluation value calculated by a group management device, thus high degree arithmetic processing must be carried out using limited hardware (H/W) resources regardless of the fact that a group management device is abolished at great pains. Further, a cost is also increased.
Further, there is conventionally proposed an elevator selective collective system as a method of effectively operating about two sets of cars ("Elevator and Escalator for Building Utility", page 26, published by Ohm Ltd.). This method is arranged such that cars towards each other respond to a car call while also responding to a landing call made after they pass. That is, an upward landing call and a downward landing call produced on a landing are regarded as a train of continuous cyclic calls and only a landing call which is located forward of an own elevator and backward of a car travelling just ahead of the own elevator is assigned to the own elevator. According to this method, when the distance between an elevator and an advancing car is made shorter, the number of assignment of landing calls made therebetween is more reduced. Therefore, the advancing car is liable to be easily cached, by which there is caused a parallel operation in which two elevators travel in the same direction at the same time.
Taking the above problems into consideration, an object of the present invention is to provide an elevator control apparatus capable of managing a plurality of cars by a simple and less expensive arrangement by an operation different from the assignment system based on evaluation and the selective collective system even if a group management device is abolished.